Fluoro-substituted phenylazopyridines



United States Patent .0 i .s gr,gg

The following examples are included in order further 3,357,968 to illustrate the invention. FLUORO-SUBSTITUTED PHENYLAZO- PYRIDIIIES EXAMPLE 1 Godfrey Wilbert, Carmel, and Henry Wetstein, Monroe,

N .Y., assignors to Nepera Chemical Co., Inc. I No Drawing. Filed Aug. 10, 1964, Ser. No. 388,713 I 3 Claims. (Cl. 260-456) NH2 ABSTRACT OF THE DISCLOSURE A class of azo pyridines of the formula: 2 3-(o-fluorophenylazo)pyridine A diazonium solution is prepared by dissolving 6.9 g. X sodium nitrite in 50 ml. of water and slowly adding it to 11.1 g. (0.1 inch) of ofluoroaniline dissolved in 270 ml. of Water containing 30 ml. of hydorchloric acid, while maintaining the temperature below 5 C. To 225 ml. of where X is fluorine or trifiuoromethyl. These compounds water containing 1 of glacial acetic i is added are useful as y Stuff- 10.9 g. (0.1 irnols) of 2,6-diaminopyridine. Then 8.7 liters of ice are added and 109 g. of sodium bicarbonate. The

diazonium solution is then added rapidly with vigorous This ilfwention relates to a COmPOSitiQH of matter and agitation to the solution containing the 2,6-diaminopyrrelates more particularly to fluoro-substituted phenylazoidine. The product, 2 6 di i .3 fi o h n 1 o) py t 0f the formula: pyridine is filtered, washed with cold water and dried. The

orange solid obtained has a melting range of 132133 N=N C- I -X EXAMPLE 2 NH \I N H:

' wherein X may be fluorine or fiuoro-lower alkyl such as i the trifluoromethyl group. NH \N NHH The compounds of this invention are useful as industrial dyestufls- 2,6-diamin0-3-(p-fluorophenylazo -pyridine According to the process of this invention, the above compounds are produced by diazotizing certain fluoroaniline or amino-benzotrifiuorides of the formula:

A solution of p-fiuoroaniline is prepared, then diazotized as described in Example 1 and coupled with 2,6-diaminopyridine. The yellow dye is filtered from the reaction mixture, washed with cold water and dried. It has a melting range of l56158 C.

EXAMPLE 3 l lHr (13F: where-in X is as defined. N=N

This diazotization reaction may be eflected by reacting the selected starting compound with sodium nitrite in NH \N NH2 the presence of hydrochloric acid or nitrous acid at a tem erat'ure below 5 C. to form a diazonium salt of the g fa 2,6-diamir z0-3-(0trifluoromethylphenylazo)-pyridine A solution of o-aminobenzot-rifluoride is prepared as described in Example 1, and then diazotized and coupled X with 2,6-diaminopyridine. The orange dye obtained is filtered olf, Washed with cold water and dried. It has a melting range of 14s 149 c.

1 NaCl EXAMPLE 4 At the completion of this diazotization reaction the excess acid may be neutralized by the addition of an alkali =N z such as sodium or potassium bicarbonate.

The diazonium salt formed is then coupled at 10 C. or N H lower with 2,6-diaminopyridine of the formula:

2,6-diamino-3-(m-trifluoromethylphenylazo)-pyridine A solution of m-aminobenzotrifiuoride is prepared as NHg- N1-r described in Example 1, diazotized and coupled with 2,6-

N diaminopyridine. The yellow dye obtained is filtered off, washed with cold water and dried. It has a melting range to form the novel diazo compounds of this invention. The 0 of l27 C. diazo compound may be readily recovered from the re- It is understood that the foregoing detailed description action mixture as a precipitate. is given merely by way of illustration and that many vari- 3 4 ations may be made therein without departing from the 2. 2,641iamino-3-(o-fluorophenylazo)-pyridinc. spirit of out invention. I 3. 2,6-diamino-3-(p-fluoropheny1az0)-pyridine.

Having decribed oiir invention, what we desire to secure by Letters Patent isz' Referelmes Cited 1. A compound of the formula: 5 UNITED STATES PATENTS 1,680,109 8/192 8 ostro mislensky 2 60--156 2,029,315 2/1936 Engehnann 260--156 CHARLES B. PARKER, Primary Examiner.

wherein X is fluorine attached in the para or ortho G Assistant Examinen position. 

1. A COMPOUND OF THE FORMULA: 